1. Field of the Invention
The present invention relates to an ink-jet printing dye-fixing agent. Particularly, the present invention relates to an ink-jet printing dye-fixing agent which is applied onto a surface of a recording medium or incorporated into the recording medium for ink-jet printing. The present invention also relates to a recording paper sheet employing the dye-fixing agent.
2. Related Background Art
In recent years, computers have become popular not only in enterprises and educational facilities but also in general families. With the popularization of the computer, many kinds of printers have been developed and come to be used for outputting the data. A typical printing system is ink-jet printing, which is increasingly employed in color printing. The dyes for the ink-jet printing are generally water-soluble. The water-solubleness of the dye impairs water resistance of the printed characters and images, causing feathering or color-running by water deposition to render the printed character or picture indecipherable.
Various fixing agents have been reported for fixation of ink-jet printing dyes to improve the water resistance of the dye. For example, JP-A-56-84992 (Japanese Patent Laid-Open No.) discloses quaternized polyvinylpyridine, JP-A-60-49990 discloses polyalkylenepolyamine-dicyandiamide condensates, and JP-A-6-92012 discloses reaction products of a secondary amine with an epihalohydrin.
Conventional fixing agent for ink-jet printing dyes does not necessarily give sufficient water resistance, or may impair the color development depending on the kind of the dye. No conventional ink-jet printing dye-fixing agent is satisfactory simultaneously for the water resistance and for color development of the dye.